Remote monitoring of undersea cable systems

ABSTRACT

A method and system are provided for remotely monitoring undersea cable systems. Upon receiving a fault alert message, an optical cross-connect is set up between the subject cable station and a testing platform. Testing is conducted and a determination is made whether the fault is in the undersea portion of the network, or in the terrestrial backhaul. By making that determination early, unnecessary technician travel is reduced.

RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 11/511,714, filed Aug. 29, 2006, now U.S. Pat. No. 7,382,947,issued Jun. 3, 2008, assigned to the assignee of the present inventionand the contents of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates generally to the maintenance of underseacable systems. More particularly, the present application relates to amethod and a system for the remote monitoring of undersea cable systems,and for remotely distinguishing between faults in an undersea cablesystem and faults in the terrestrial backhaul system.

BACKGROUND OF THE INVENTION

Undersea communications cable systems are a critical part of today'scommunications infrastructure. A single optical cable, resting on theocean floor between continents, may be on average capable oftransmitting over 8 million concurrent telephone calls. Because of thathigh transmission density, the downtime resulting from a fault in thecable or its supporting plant equipment is extremely expensive.

Undersea cable systems, by their nature, require maintenance procedures,maintenance equipment and technician expertise that are different fromthose required in a terrestrial-based system. For that reason, it isoften critical to quickly and efficiently determine whether a fault islocated in the undersea cable system or in the supporting backhaul orother equipment.

An undersea cable station includes backhaul plant interfacing equipmentand other associated equipment. Repairs to undersea cable faults aretypically undertaken at the undersea cable station. Undersea cablestations are frequently located in remote coastal areas that are awayfrom population centers. While undersea cable stations were at one timeoften manned 24×7 with skilled, on-site technicians, that is no longerthe case, and a technician must now be dispatched to the station when afault alarm is received during unmanned hours. Because of the remotelocations of the stations, the dispatch is time-consuming, and extendsexpensive downtime.

Presently, where a central network operating center for the underseacable system is employed, the decision-making occurs there. That centralpoint, however, is responsible for all carrier traffic and is slow toreact to network troubles. It is furthermore difficult for the networkoperating center to determine whether a fault is located in the underseacable system, or is in the backhaul or associated terrestrial equipment(i.e., whether the fault is “wet” or “dry”). That is because the centralnetwork operating center for the undersea cable system can only see andcontrol the wet side operations.

95% of the undersea cable systems, however, do not contain a centralnetwork operations center. There is no tie-in between facilitymonitoring on undersea cable networks and facility monitoring on theterrestrial network that feeds into the undersea networks. In such aconfiguration, there is again no way to distinguish between “wet” and“dry” faults.

In either case, valuable time is wasted in responding to a fault alarm.For example, if a technician is dispatched to the undersea cablestation, there is a possibility that it will be discovered that thefault is in the backhaul, and the elapsed travel time to the station hasbeen wasted. Conversely, a technician dispatched to the terrestrialplant may discover that the fault is in the undersea cable system.Dispatching technicians in both directions simultaneously is expensiveand confusing.

There therefore remains a need for a cost-effective technique tonon-intrusively monitor and diagnose fault alarms in undersea cablesystems and the associated terrestrial plant and to do that workquickly.

SUMMARY OF THE INVENTION

The invention addresses the needs described above by providing a methodand system for remotely monitoring and diagnosing fault alarms inundersea cable systems. One embodiment of the invention is a method forremotely monitoring undersea cable systems. The method comprises thesteps of receiving alarm information from an undersea system cablestation; requesting, from a database, traffic facility informationpertaining to the alarm information; receiving the traffic facilityinformation; transmitting to an optical switch, a command to create across-connect; transmitting, to a test set platform, commands to performa test on the undersea cable system; and receiving test information fromthe test set platform.

The method may include the step of placing a determination of whetherthe alarm relates to an underwater fault or a terrestrial fault on atrouble ticket. Based on the interpreting step, it may be determinedwhether a service call out is necessary to address the alarm and whereto send the technician, or a repair time may be estimated.

The method may further include the step of low-loss, non-intrusivelymonitoring, at the undersea system cable station, a high-speedwavelength. That monitoring may be performed by a value-added module(VAM) which is a splitter at the undersea system cable station.

The test set platform may be an Agilent N2X test set. The step oftransmitting to an optical switch, a command to create a cross-connect,may be performed via transaction language 1 (TL1). The commands toperform a test on the undersea cable system may include tool commandlanguage (TCL) commands. The database may be the Undersea NetworkAdministration Database (UNAD), which is an undersea circuit facilitydatabase.

Another embodiment of the invention is a system for remotely monitoringan undersea cable system. The system comprises an automatedalarm/monitoring platform and a value-added module (VAM) inserted ontransmit and receive high speed wavelengths at a cable station of theundersea cable system. The VAM is configured to monitor a signal in theundersea cable system. The system further includes a database platformcomprising traffic facility information, the database being configuredto respond to a request from the automated alarm/monitoring platform fortraffic facility information pertaining to the alarm information. Atesting platform of the system is configured to receive instructionsfrom the automated alarm/monitoring platform to conduct a performancetest on the monitored signal, to conduct the performance test inresponse to the instructions, to make a determination whether the faultis in the undersea cable system, and to forward the determination to theautomated alarm/monitoring platform.

The system may further include an optical switch configured forreceiving a command from the automated alarm/monitoring platform and forestablishing, in response to the command, a cross-connect between theVAM and the testing platform.

The command to create a cross-connect may be a TL1 command. Theautomated alarm/monitoring platform may further be configured to place adetermination of whether the alarm relates to an underwater fault or aterrestrial fault on a trouble ticket.

The automated alarm/monitoring platform may be configured to determinewhether a service call out is necessary to address the alarm, based onthe determination whether the fault is in the undersea cable system. Theautomated alarm/monitoring platform may be configured to estimate arepair time.

The VAM may further include a splitter at the undersea system cablestation. The test set platform may be an Agilent N2X test set.

The instructions to conduct a performance test on the undersea cablesystem may be TCL commands. The database may be a UNAD database.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic representation of a cable station and relatednetwork components according to one embodiment of the invention.

FIG. 2 is a schematic representation of a system for monitoring underseacable installations according to one embodiment of the invention.

FIG. 3 is a timing chart depicting a method according to one embodimentof the invention.

DESCRIPTION OF THE INVENTION

With the rising costs of operating and maintaining undersea cablesystems and cable stations, a tool is required to remotely monitor andsupport those systems, especially during out-of-office hours. Theinventors have developed remote monitoring equipment and software is toimprove the repair decision-making process during diagnostics. Theinventive system quickly facilitates fault isolation to “wet-side”undersea cable troubles, or to “dry-side” backhaul facility troubles.That quick determination reduces the number of out-of-hours callouts andits associated expenses. During manned hours, technical support isengaged to access the network at the same time as the on-site workforce.Furthermore, with quicker fault isolation, traffic facility outage timeis reduced and loss of revenue protected.

The hardware and software utilized in the inventive system isnon-intrusive and always connected to the network. Through the use ofautomatic alarm detection software, facility databases, and automaticdiagnostic scripting, fault isolation is done quickly. That additionalfault isolation information is added to the trouble ticketing system,and prioritization and callout determination is made based on thatinformation.

Through the use of a second test port with the cable station equipmentthat is not waiting for an alarm to be detected, the high-speedwavelengths of the undersea cable system are constantly monitored. Thedata collected can be used to compare against service level agreementsand to chart trends of service performance. Troubles may then beproactively avoided by taking preventive maintenance actions.

The inventive design allows quick fault isolation and determination ofthe need for call-out. Operations expenses are reduced in an environmentof rising operations costs. The inventive system further protectsagainst revenue loss due to extended network outages. Through theautomation of the fault detection and reporting process, faultdiagnostic information is provided in simple terms in the troubleticket, making it easier and faster to resolve network troubles.

The monitoring system 100 of the invention will be described withreference to FIG. 1. A cable station 110 includes a digitalcross-connect system (DXCS) 120 connected through network protectionequipment (NPE) 135 to an optical distribution frame (ODF) 140. The ODFconnects to line termination units (LTUs) 130 that terminate terrestrialbackhauls and the undersea plant. Other similar connections are made toother line termination units LTU-n 131 from the DXCS and from othercommon carriers (OCC) 125.

Inserted on the transmit and receive high-speed wavelengths (2.5 Gb/s or10 Gb/s) within the ODF 140 are value-added modules (VAMs) 141 orsplitters. The VAMs 141 permit low-loss non-intrusive monitoring of thesignal. The monitored signal is forwarded to an optical switch 150. Inthe embodiment preferred by the inventors, an optical switchmanufactured by Calient Networks of San Jose, Calif. is used.

A cross-connect is made at the optical switch 150, whereby the tappedsignal 151 is monitored by a test set platform 152. The test setplatform 152 may be integrated with the optical switch 150 as shown inFIG. 1, or may be a separate unit. In a preferred embodiment of theinvention, the test set platform is an Agilent N2X test set.

The test set platform 152 has the ability to monitor alarm, event andperformance information for the tapped high speed wavelength and theassociated wavelengths sub-rate signals 151. For example, a TCL scriptin the test set platform 152 may control the activation and deactivationof lasers and receivers, and interpret the resulting signals. Analysisof the alarm information of the high-speed wavelength by the test setplatform 152 allows for a quick determination of whether a wet or dryfailure has occurred. Further, any or all particular sub-rate signalscan be monitored to further isolate which terrestrial facilities havefailed. In a preferred embodiment, automation is achieved through theuse of software Perl scripts, TL1 software scripts to control theCalient optical switch and TCL software scripts to control the AgilentN2X test set.

As will be described below, a connection between the optical switch 150and a long distance carrier intranet 170, such as the AT&T Intranet, isused to initiate the necessary cross-connects and to carry testingcommands and results from remote facilities 180 including remoteterminal units (RTUs) 181.

A system 200, according to one embodiment of the invention, is shown inFIG. 2. That system includes an automated alarm/monitoring platform 210,which, in conjunction with other elements of the system 200, performsalarm monitoring methods according to the invention. In a currentlypreferred embodiment, the platform runs a scripting software such asRUBY scripting software, a proprietary scripting software of AT&T. Thealarm/monitoring platform 210 may run out of a transport service centerof a long distance carrier.

A single long distance backhaul path is shown in FIG. 2, from a DXCS230, through NPE 231 to LTU 232, as described above. The path continuesthrough additional LTU 233 to NPE 234, etc. Each element of the path ismonitored using an interface 240, providing manual access 250.

The automated alarm/monitoring platform 210 receives alarm information224 from the undersea cable systems DXCS 230. The platform 210 thenretrieves traffic facility information from a database 220, usinginformation from the alarm as a retrieval key. The database 220 may be aUNAD database in a GeoLink platform 215, UNAD and GeoLink beingproprietary databases of AT&T.

Based upon the traffic facility information received from the database220, the automated alarm/monitoring platform 210 sends commands via TL1to create a cross-connect on the optical switch 228 between test setplatform 225 (e.g., an Agilent OmniBER XM test set) and a VAM (notshown). The platform 210 sends TCL commands to the test set platform225, initiating and controlling the testing procedure. The informationthat is obtained from the test set platform 225 is then interpreted bythe automated alarm/monitoring platform 210. A determination is made inthe alarm/monitoring platform 210 as to whether the fault is a wet-sideor dry-side fault. In an alternative embodiment, the determination ismade in the test set platform 225 and forwarded to the fault monitoringplatform 210.

In either case, that wet vs. dry determination, together with associatedinformation, is placed by the alarm monitoring platform 210 in a troubleticket (not shown). If the cable station is unmanned, a transportmaintenance center such as the AT&T International Transport MaintenanceCenter (ITMC) will make a decision as to whether a call-out is necessaryand prioritize the trouble ticket. If the cable station is manned, theticket will also be picked up by the on-site workforce and will help inisolating the fault and minimizing traffic outage. Additionally, Tier IIand III technical support can assist quickly in determining where thefault lies and what corrective action can be taken. Decisions on repairtimes and whether restoration is necessary will also occur quicker andmore efficiently.

A method for monitoring faults in an undersea cable system according toone embodiment of the invention will now be described with reference tothe timing chart 300 of FIG. 3. The process is triggered when a receivepath alarm 360, including a target ID/access ID (TID-AID) from the DXCS305, is transmitted from the DXCS in the cable station to thealarm/monitoring platform 320. The alarm/monitoring platform 320 thentransmits at least one query 361 to the database 330 to retrieve trafficfacility information. In response, the database 330 transmits trafficfacility information 362 back to the alarm/monitoring platform 320.

In a preferred embodiment using the proprietary UNAD database, twoexchanges (not shown) actually take place between the alarm/monitoringplatform and the UNAD database. In response to a first UNAD queryincluding a common language facility identifier (CLFI) (i.e., viaGEOLINK Platform), the UNAD database provides InternationalTelecommunications Unit (ITU) facility information. A second query isthen sent from the alarm/monitoring platform, including the ITU facilityinformation, UNAD #, and Cable Station ID. In response, the UNADdatabase 330 provides CLFI hierarchy and/or slotting within theSynchronous Transport Module level 64 (STM-64) or the STM-16. Ifrequired, assignment mapping to an optical switch alias is alsoprovided.

The alarm/monitoring platform 320 then sends TL1 commands 363 to anoptical switch 340 to establish a cross-connect. The TL1 commandsactivate a specific port to a particular VAM. The cross-connect 364 isset up by the optical switch 340 between the VAM 310 in the cablestation and the Agilent test platform 350. The optical switch 340 maysend a confirmation 365 to the alarm/monitoring platform 320 that thecross-connect was successfully established.

The alarm/monitoring platform 320 then sends TCL commands 366 to thetest platform 350. The commands 366 include instructions to performtests. The test platform 350 then runs the tests 367 via a TCL script,over the cross-connect with the cable station 310. The test results,which may include a “wet/dry” determination 368, are then transmittedfrom the test platform 350 to the alarm/monitoring platform 320. Thetest results may also include specific results such as SDH overhead. Thealarm/monitoring platform 320 creates and routes a ticket that includesat least some of the test results.

The benefits of implementing the inventive solution are a reduction inoperations and maintenance expenses and increased revenue protection. Asthe cost of operating and maintaining undersea cable systems continuesto rise, the trend is to reduce the staffing hours. To reduce hours andthus costs of labor and utilities, the monitoring and trouble resolutionmust be moved to a remote network operation center. The center willdetermine whether or not to call out to station personnel to fix atrouble.

By determining whether the fault is a wet-side or dry-side fault,unnecessary call-outs and thus costs can be avoided. Furthermore,trouble resolution is quicker because a fault is better isolated to aparticular piece of equipment making up the network. By resolvingnetwork outages quicker, operations expense avoidance is achieved andprotection against loss of revenue is also achieved.

The foregoing Detailed Description is to be understood as being in everyrespect illustrative and exemplary, but not restrictive, and the scopeof the invention disclosed herein is not to be determined from theDetailed Description, but rather from the claims as interpretedaccording to the full breadth permitted by the patent laws. For example,while the method of the invention is described herein with respect toparticular databases, scripting languages and command languages, themethod and apparatus of the invention may be embodied by any systemperforming the steps or embodying the structure set forth in the claims.It is to be understood that the embodiments shown and described hereinare only illustrative of the principles of the present invention andthat various modifications may be implemented by those skilled in theart without departing from the scope and spirit of the invention.

1. A method for remotely monitoring an undersea cable system, the methodcomprising the steps of: creating a cross connect through an opticalswitch between a test platform and a value added module inserted on thetransmit and receive high-speed wavelengths in a cable station of theundersea cable system; running tests in the cable station from the testplatform over the cross connect; and determining, from results of thetests, whether an alarm relates to an underwater fault or a terrestrialfault.
 2. The method of claim 1, further comprising the step of: placinga determination of whether the alarm relates to an underwater fault or aterrestrial fault on a trouble ticket.
 3. The method of claim 1, furthercomprising the step of: based on the results of the tests, determiningwhether a service call out is necessary to address the alarm.
 4. Themethod of claim 1, further comprising the step of: based on the resultsof the tests, estimating a repair time.
 5. The method of claim 1,wherein the test set platform is an Agilent N2X test set.
 6. The methodof claim 1, wherein the step of creating a cross connect through anoptical switch, is performed via TL1.
 7. The method of claim 1, furthercomprising the step of: transmitting TCL commands to perform the testson the undersea cable system.
 8. The method of claim 1, furthercomprising the step of: retrieving traffic facility informationpertaining to the alarm.
 9. The method of claim 8, wherein theinformation is retrieved from a UNAD database.
 10. A system for remotelymonitoring an undersea cable system, comprising: an automatedalarm/monitoring platform; a value-added module (VAM) inserted ontransmit and receive high speed wavelengths at a cable station of theundersea cable system, the VAM being configured to monitor a signal inthe undersea cable system; a testing platform for conducting aperformance test on the monitored signal, and making a determinationwhether a fault is an undersea fault or a terrestrial fault; an opticalswitch configured for receiving a command from the automatedalarm/monitoring platform and for establishing, in response to thecommand, a cross-connect between the VAM and the testing platform, andfor establishing the cross-connect.
 11. The system of claim 10, whereinthe command to establish a cross-connect is a TL1 command.
 12. Thesystem of claim 10, wherein the automated alarm/monitoring platform isfurther configured to place the determination of whether the alarmrelates to an underwater fault or a terrestrial fault on a troubleticket.
 13. The system of claim 10, wherein the automatedalarm/monitoring platform is further configured to determine whether aservice call out is necessary to address the alarm, based on thedetermination whether the fault relates to an underwater fault or aterrestrial fault.
 14. The system of claim 10, wherein the automatedalarm/monitoring platform is configured to estimate a repair time. 15.The system of claim 10, wherein the value-added module (VAM) furthercomprises a splitter at the undersea system cable station.
 16. Thesystem of claim 10, wherein the test set platform is an Agilent N2X testset.
 17. The method of claim 10, wherein the testing platform isconfigured to receive TCL commands from the automated alarm/monitoringplatform to conduct the performance test on the monitored signal.